For America I think the 80's are crucial- the rise of the nostalgia industry, Reaganism and the insistence on the family as the defacto political unit. Re: Jameson's architectural point, the reaction against modernist architecture degrading the 'fabric of the traditional city and its neighborhood culture' was also the first point where America at large cared for architecture to begin with. 40 years post war the self evidence of American exceptionalism wanes, accelerated by Vietnam and 70's economic stagnation, and we have a collective waking up moment to a culture that never invested in the trappings of the traditional to start, at least not to the level of other parts of the world. The american inferiority complex w/r/t europe could come into play here.